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Concepts Of Physics MCQ Edition [Volume 2]PhysicsAlternating Current

A metal wire is heated by an alternating current with a peak value of 14 A . To achieve the same heating effect, a constant current i can be applied where i is

Options

  1. A7 A
  2. B14 A
  3. Cabout 20 A
  4. Dabout 10 A

Correct answer

D. about 10 A

Step-by-step solution

The heating effect of an alternating current is equivalent to the heating effect of a direct (constant) current equal to its root mean square (RMS) value. The RMS value of an alternating current is given by I_ rms = I₀ 2 Given the peak current I₀ = 14 A I_ rms = 14 2 = 7 2 A Substituting 2 1.414 I_ rms = 7 1.414 = 9.898 A This is approximately 10 A .

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